Patent EA-003123-B1 (EA)
Title: Flexible stamp apparatus for printing three-dimensional spherical or curved objects
IPC: B41F17/30
Filed: 2000-04-10
Abstract: 1. Apparatus for printing three dimensional objects, particularly objects having a substantially spherical shape, comprising a pad for printing by means of pad printing, wherein said pad is made of silicone with a determined thickness and shape, which is mounted on a hollow pad holder (1) made of an undeformable material which constitutes an isolated space together with said silicone shape (2), which is supplied with compressed air and which is connected to a pressure vessel by means of a main element (4) provided therefor through an opening (3), characterised in that the apparatus is arranged in open loop wherein there is provided an additional separate aperture (8) for a separate inlet and outlet of air (3, resp. 8), with a pressure regulating unit (6) enabling to keep the pressure in the pad greater than or at a preset level P, wherein said pressure regulating unit (6) regulates the compressed air which enters the regulating unit (6) through a supply main (7). 2. Apparatus according to the preceding claim, characterised in that there is provided an over-pressure valve (9) which is connected to the outlet (8) of the pad holder (1) through a discharge conduit (4'). 3. Apparatus according to claim 1 or 2, characterised in that the pad is provided with a pilot valve (13) which is fed through a compressed air main (11), and with a measuring unit (12) for measuring the pressure in the pad and controlling the pressure regulating unit (6) through a control pressure conduit (14), which mutually connects the pilots valve (13) and the pressure regulating unit (6). 4. Apparatus according to one of the preceding claims, characterised in that said pad (25) comprises pressure sensors (19) for measuring the pressure of the pad (25), wherein the signal (s) delivered by said sensors (19) is transmitted to the electronical control unit (18). 5. Apparatus according to one of the preceding claims, characterised in that said pad (25) comprises a buffer vessel (20) and a nonreturn valve (21), wherein the inlet is provided with a pressure regulator (22) which builds up a preset pressure between the printing cycles in said buffer vessel (20) and wherein said nonreturn valve (21) prevents the air which is pressed out of the pad from returning to the buffer vessel (20) during a printing stage, wherein subsequently the air pressed out from the pad leaves the apparatus through the overpressure valve (9), and wherein the supply main (4) has a sufficient diameter for supplying the needed air flow each time the pad returns to its rest position (A) after an inking or printing cycle. 6. Process for printing surfaces of an object by means of an apparatus according to one of the preceding claims, consisting in first pressing the pad in an open circuit against an initially inked surface, whereupon the half spherical surface of the pad, which is in close contact with this inked surface, is flattened so that the figures to be printed are transferred on the surface of the pad, in subsequently removing said pad from the original surface in order to enable the latter to recover its initial half spherical form again, and in subsequently pressing said pad against the three dimensional spherical and/or curved surface in such a way that said pad encompasses at least a spherical or curved part of said object, and in bringing the pad surface bearing the inked figure into contact with the surface of said object (30) thereby to transfer this inked figure on the desired spherical or curved part of the receiving object.